Aircraft are known that are equipped with a fuselage defining an inner space, having wings connected to the fuselage for example at a central portion thereof and a wing box arranged in the inner space of the fuselage and configured to connect the wings to the fuselage.
The aircraft generally comprise moreover one or more landing gear assemblies configured to deploy from and retract into one or more landing gear compartments arranged in the fuselage. Each landing gear compartment forms a hole in the fuselage, because unlike the rest of the inner space of the fuselage, the landing gear compartment is not pressurized.
During aircraft maneuvers, for example ascent or descent (vertical movement), the wings and the fuselage undergo significant opposite bending stresses such that the fuselage, more specifically its lower portion, is working in compression (on ascent) or tension (on descent). It will be noted that the compressive stresses are greater than the tensile stresses.
A zone is formed at the level of each landing gear compartment that is less stiff than elsewhere on the fuselage, so that the fuselage of the aircraft is generally provided with a connecting device configured to compensate for the loss of stiffness of the fuselage resulting from each landing gear compartment. Said connecting device is very often formed by a keel beam.
In some fuselages, the keel beam is connected on the one hand to a front portion of the fuselage and on the other hand to a rear portion of the fuselage.
In other fuselages, the keel beam is connected on the one hand to the wing box and on the other hand to the rear portion of the fuselage. Said beam is not connected to the front portion of the fuselage.
Fuselages are also known in which the keel beam is connected to both the front and rear portions of the fuselage and to the wing box. The keel beam is connected to the wing box and is configured to transfer stresses undergone by the fuselage to the wing box, said stresses working in shear with respect thereto.
Other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.